CVE-2016-9599 in puppet-tripleo
Summary
by MITRE
puppet-tripleo before versions 5.5.0, 6.2.0 is vulnerable to an access-control flaw in the IPtables rules management, which allowed the creation of TCP/UDP rules with empty port values. If SSL is enabled, a malicious user could use these open ports to gain access to unauthorized resources.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/03/2023
The vulnerability identified as CVE-2016-9599 affects puppet-tripleo versions prior to 5.5.0 and 6.2.0, specifically targeting the iptables rules management component within the OpenStack deployment automation framework. This access-control flaw represents a critical weakness in network security configuration where the system permits the creation of TCP/UDP firewall rules with empty port specifications, effectively creating wildcard port entries that bypass normal port restrictions. The vulnerability resides in the underlying firewall rule generation mechanism that fails to properly validate port parameters during rule creation, allowing for malformed rule entries to be processed and implemented in the network security configuration.
The technical implementation of this vulnerability stems from inadequate input validation within the iptables rule management system of puppet-tripleo. When administrators or automated processes attempt to create firewall rules, the system does not properly validate that port fields contain valid numeric values or appropriate port ranges, resulting in rules that can match any port number. This flaw creates a pathway for malicious actors to exploit the weakened firewall configuration, particularly when SSL encryption is enabled within the OpenStack environment. The empty port values in the iptables rules effectively create open ports that can be leveraged by unauthorized users to establish connections to services that should otherwise be restricted.
The operational impact of this vulnerability extends beyond simple network access issues, as it directly compromises the security boundaries that protect critical infrastructure components within OpenStack deployments. When SSL is enabled, the vulnerability becomes particularly dangerous because attackers can utilize the open ports to perform man-in-the-middle attacks, intercept encrypted communications, or gain unauthorized access to backend services that rely on SSL for protection. The flaw essentially undermines the principle of least privilege by allowing unauthorized network access that bypasses normal port-based restrictions, potentially enabling attackers to reach sensitive components such as database services, API endpoints, or administrative interfaces that should be protected by proper firewall rules.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and demonstrates how inadequate input validation can lead to security misconfigurations that compromise network defenses. The attack surface expands significantly when considering that tripleo deployments often manage complex cloud infrastructures where multiple services operate on various ports, and the presence of empty port rules creates unpredictable network exposure. From an attacker perspective, this vulnerability maps to ATT&CK technique T1046, which involves network service scanning and exploitation, as the open ports created by the malformed rules provide additional attack vectors for reconnaissance and exploitation activities.
Mitigation strategies for CVE-2016-9599 require immediate implementation of version updates to puppet-tripleo 5.5.0 or 6.2.0, which contain the necessary patches to address the iptables rule validation flaw. Organizations should conduct comprehensive network security assessments to identify any existing malformed firewall rules that may have been created due to this vulnerability and remediate them by removing or correcting the empty port entries. Additionally, implementing automated network monitoring solutions that can detect anomalous port configurations and unauthorized firewall rule modifications will help prevent similar issues from recurring. Security teams should also review and validate all firewall rule configurations in their tripleo deployments to ensure proper port validation and enforcement, while maintaining strict access controls over the configuration management systems that generate these rules. The remediation process must include thorough testing of updated configurations to ensure that legitimate network services continue to operate properly while eliminating the security gaps introduced by the empty port rule creation.